As we age, our skin undergoes changes such as becoming thinner, more easily damaged and less elastic. In addition, lifetime exposure to UV-A and UV-B radiation, together with other environmental factors that induce the formation of free radicals, such as pollution from traffic fumes, ozone, cigarette smoke etc, causes changes to the skin. These changes, including lines and wrinkling, actinic lentigines, dyspigmentation, rough skin, actinic telangiectasia and further loss of skin elastic function are due to direct UV-mediated damage to cells and indirectly mediated damage caused by the generation of free radicals in cells and tissues. This is generally termed photoageing and can account for up to 90% of the skin changes we associate with ageing.
The deleterious effects of UV radiation are generally believed to be due to the creation of free radicals. These highly reactive species may react with and damage DNA molecules in the skin (or elsewhere). Similar effects can also be attributed to radiation in the visible part of the spectrum.
Our hair also is damaged by exposure to UV-A and UV-B radiation, and other environmental factors that induce the formation of free radicals, such as those mentioned above. Furthermore, exposure to heat during drying and/or styling, and chemical treatment of the hair (eg perming, straightening, dyeing and/or bleaching) can also generate free radicals. Free radicals are implicated in the process of damage to hair, which may be observed as a reduction in shine, feel and/or fading of hair colour.
It is known to use antioxidant compounds as free radical quenchers, thereby mitigating the effects of free radical formation.
There have now been devised compositions and methods involving combinations of antioxidant agents which have been found to be particularly effective in protecting the skin and hair against free radical-induced damage.